AstraZeneca (AZN+0.5%) may be a step behind Roche (RHHBY.OB+0.9%), Bristol-Myers (BMY+0.3%), and Merck (MRK-1.3%) when it comes to developing immunotherapies to treat cancer, but "the field is still very open for combinations and [AZN is] very much in the race," the company's head of biologics Bahija Jallal says.

The "breadth" of AZN's pipeline and the "pace of cancer drug development" may help AZN catch up to industry leaders quickly, Reuters notes.

One promising candidate is the PD-L1 blocker MEDI4376 which may prove most effective when paired with other drugs such as tremelimumab which "works in a similar way to BMY's Yervoy."